Burner tube and venturi for gas grill

ABSTRACT

The present inventions provide, among other things, tapered burner tubes having raised gas ports and a smooth interior surface free from obstructions. Venturi members creating a smooth flow of the gas/air mixture along the top of the burner tube are also provided.

STATEMENT OF PRIORITY

This application is a continuation-in-part of U.S. application Ser. No.14/880,654, filed Oct. 12, 2015, and claims priority thereto andincorporates by reference such application in its entirety.

FIELD OF THE INVENTION

The present inventions relate to burners and venturis for use in gasappliances such as gas grills. More particularly, the present inventionsrelate to burner tubes (including tapered burner tubes) having raisedgas ports and a smooth interior surface, and/or to venturis that providesmooth and consistent flow of the gas/air mixture along the length ofthe burner tube adjacent to the gas ports.

BACKGROUND OF THE INVENTION

Burners and burner tube assemblies, including those used in gas grills,are well known. Most conventional gas grills include burner tubeassemblies that provide a plurality of burner tubes, gas valves and agas distribution manifold. Each burner tube has a length defined by anopen end and a closed end and a plurality of outlet ports along thelength of the burner tube between the open and closed ends. The open endof the burner tube typically includes an air shutter that is used toadjust the gas and combustion air mixture, as well as a venturi regionto increase the velocity of the gas/air mixture in the tube. The openend of the burner tube is connected to the neck of a gas control valve,which is in fluid communication with a gas distribution manifold, whichis in fluid communication with a gas source such as a tank.

For cost, manufacturing and other reasons, many conventional burnertubes are constructed from hollow welded circular tubing, often madefrom stainless steel. A venturi region is typically formed by pinchingthe tube near the open end of the burner tube. The venturi increases thevelocity of the fuel/air mixture from the gas nozzle into the burnertube. An air shutter is also typically provided on the open end of theburner tube to adjust the fuel to air mixture.

Also for cost and other manufacturing reasons, the gas ports of typicalburner tubes are punched into the tube from the outside of the tube tothe inside, either on the top or sides of the tube. This results inburrs or other obstructions on the inside of the burner tube that candisrupt the flow of the fuel/air mixture and provide poor flame quality.Moreover, the flames produced by such burner tubes typically sitdirectly on the surface of the burner tube itself. This increases thetemperature of the burner tube and can result in increased corrosion andclogging of the ports as well as a shorter life of the burner tube. Inaddition, many known burner tubes have a substantially uniformcross-section along their length that can result in uneven orinconsistent fuel pressure along the length of the tube. This can alsonegatively affect flame quality.

Thus, there is a need for improved burner tubes that provide improvedflame characteristics and quality and which increase the life of theburner tube. There is also a need for burner tubes that enable smoothfuel/air flow throughout their length, as well as consistent pressurethroughout the length of the burner tube. The present inventions solvethe above described and other deficiencies and provide new features andadvantages over known burner tubes.

There is also a need for improved venturis for use with burner tubes,either alone or in conjunction with the burner tubes of the presentinventions. For example, it is possible, due to variation between gastrain components, that turbulence can form at the upper portion of theburner tube adjacent to the gas outlet port. This can result in poorflame quality and/or the failure to ignite the gas/air mixture. Thus,there is a need for venturis that direct the turbulent gas/air mixtureto the bottom of the burner tube and provide a smooth and consistentflow of the gas/air mixture along the top of the burner tube adjacent tothe gas ports. This results in a more stable gas/air delivery system andbetter flame quality. The present inventions solve the deficiencies ofknow venturis and provide new features and advantages over knownventuris, alone or in conjunction with the burner tubes of the presentinventions.

SUMMARY OF THE INVENTION

In general, the burner tubes and venturis of the present inventions arepart of burner assemblies used with gas grills. The present inventionspreserve the advantages of known burner tubes and venturis and providenew features and advantages, some of which are described below andothers which will be apparent to those of ordinary skill in the art.

In accordance with the present inventions, a venturi member for use in aburner tube for a gas grill, the burner tube having a length, a top withgas ports and a bottom is provided. The venturi member includes a frontface having a top and a bottom, the front face including an opening toaccommodate a neck of a gas valve; a top flange extending rearwardlyfrom the top of the front face and a substantially parallel bottomflange extending rearwardly from the bottom of the front face; adownwardly sloping top constricting flange extending rearwardly from thetop flange and an upwardly sloping bottom constricting flange extendingrearwardly from the bottom flange, the top constricting flange andbottom constricting flange converging to form a throat area. An upperarcuate portion extending rearwardly from the top constricting flangeand a lower arcuate portion extending rearwardly from the bottomconstricting flange are also provided.

The venturi member may further include an upper arcuate portion that hasa concave shape generally adjacent to the top of the burner tube and/ora lower arcuate portion that has a concave portion and a convex portiongenerally adjacent to the bottom of the burner tube. In a preferredembodiment, the upper arcuate portion occupies the space whereturbulence may form along the top of the burner tube and adjacent to thegas ports. Also in a preferred embodiment, a first turbulence area iscreated in the concave portion of the lower arcuate portion and a secondturbulence area is created adjacent to the end of the convex portion ofthe lower arcuate portion. The top constricting flange may be arcuate.

A burner for use in a gas grill is also provided. It includes a taperedburner tube having an open end, a closed end and a substantially hollowand smooth interior which is free of burrs or other obstructions. Theburner tube includes an upper surface, the upper surface including aplurality of gas ports having a height projecting above the uppersurface of the tube and an opening at the top of the height, the openinghaving a diameter. A venturi member at the open end of the burner tubeis also provided, the venturi member including a front face having a topand a bottom, the front face including an opening to accommodate a neckof a gas valve; a top flange extending rearwardly from the top of thefront face and a substantially parallel bottom flange extendingrearwardly from the bottom of the front face; a downwardly sloping topconstricting flange extending rearwardly from the top flange and anupwardly sloping bottom constricting flange extending rearwardly fromthe bottom flange, the top constricting flange and bottom constrictingflange converging to form a throat area; an upper arcuate portionextending rearwardly from the top constricting flange wherein the upperarcuate portion has a concave shape generally adjacent to the top of theburner tube; and, a lower arcuate portion extending rearwardly from thebottom constricting flange wherein the lower arcuate portion has aconcave portion and a convex portion generally adjacent to the bottom ofthe burner tube.

A preferred venturi may further include an upper arcuate portion thatoccupies the space where turbulence may form at the top of the burnertube adjacent to the gas ports and a first turbulence area is created inthe concave portion of the lower arcuate portion and a second turbulencearea is created adjacent to the end of the convex portion of the lowerarcuate portion.

In a preferred burner tube embodiment, the gas port height of the burneris between approximately 0.020 and 0.062 inches and the opening diameteris between approximately 0.075 and 0.110 inches. More specifically andpreferred, the gas port height is approximately 0.060 inches and theport diameter is approximately 0.093 to 0.099 inches. In addition and aspreferred, the ratio of gas port height to gas port opening diameter isbetween approximately 0.640 and 0.650, and preferably greater than 0.5.

In a preferred burner tube embodiment, the height of the gas ports isbetween 0.020 and 0.062 inches and the area of the gas port opening isbetween 0.006 and 0.008 square inches. In a particular preferredembodiment, the height of the gas port is approximately 0.060 inches andthe area of the opening is approximately 0.007 square inches.Alternatively, the port opening may be generally circular and have adiameter. In such an embodiment, the height of the gas port is between0.020 and 0.062 inches and the diameter of the opening is between 0.075and 0.110 inches. More particularly, the height of the gas port isapproximately 0.060 inches and the diameter of the opening isapproximately 0.098 inches. An air shutter that cooperates with the openend of the burner tube and venturi member may also be provided.

Accordingly, it is an object of the present inventions to provide asafe, reliable burner tube that efficiently operates over a wide rangeof gases and mixtures and a wide range of input pressures.

It is another object of the present inventions to provide a taperedburner tube that enables consistent pressure along the length of thetube.

Still another object of the present inventions is to provide a burnertube having a smooth interior surface that enables laminar fluid flowalong the length of the interior of the tube.

Yet another object of the present inventions is to provide raised gasports that enable better flame characteristics and help maintain acooler burner tube temperature.

Still yet another object of the present inventions is to manufacture theburner tube by forming the raised gas ports from what will be the insideof the burner tube to what will be the outside of the burner tube sothat the interior of the burner tube is smooth and free from burrs ofother obstructions.

An additional object of the present inventions is to reduce corrosionand gas port clogging of the burner tube.

Still an additional object of the present inventions is to providelarger gas port openings that provide improved flame characteristics andare less susceptible to corrosion, yet are not prone to backflash orflame pull back into the burner tube when in use.

Yet an additional objection of the present inventions is to enablegreater material selection as well as manufacturing and cost advantages.

A further object of the present inventions is to provide a burner tubehaving improved flame characteristics and less material degradation.

Still yet another object of the present inventions is to provide animproved burner tube having a tapered cross-section, a venturi memberand an air shutter that cooperates with the open end of the burner tubeto adjust the fuel/air mixture.

Still a further object of the present inventions is to provide animproved venturi member and including one that may function with aburner tube having a non-circular cross-section and which improves flamequality and/or ignition.

Still yet an additional object of the present inventions is to providean improved venturi member that produces the smooth flow of the gas/airmixture along the top of the burner tube adjacent to the gas outletports.

Still yet a further object of the present inventions is to provide animproved venturi member that forces any turbulence in the gas/airmixture to the bottom of the burner tube and away from the gas outletports.

Still yet a further object of the present inventions is to provide animproved venturi member that provides smooth flow of the gas/air mixtureadjacent to the gas ports of the burner tube and provides a stable flowof the gas/air mixture and which improves flame quality and/or ignition.

INVENTOR'S DEFINITION OF THE TERMS

The following terms which may be used in the various claims and/orspecification of this patent are intended to have their broadest meaningconsistent with the requirements of law:

As used herein, “front” or “forward” is used by reference to the frontor toward the front of a gas grill which typically includes the controlpanel, gas control knobs and the like. However, it is understood thatthe present inventions may be applicable to grills that have sidecontrols and burner tubes that extend from side to side of the grill.

As used herein, “rear” or “rearward” is used by reference to the back ortoward the back of a typical gas grill.

As used herein, “air shutter” shall mean the device, typically found atthe open end of the burner tube, that cooperates with the open end ofthe burner tube to permit the adjustment of an opening of the burnertube to control the fuel to combustion air mixture.

As used herein, “ignition system” shall mean devices that are capable ofgenerating sparks to ignite the fuel/air mixture emitted from the outletports of a burner tube.

Where alternative meanings are possible, in either the specification orclaims, the broadest meaning is intended consistent with theunderstanding of those of ordinary skill in the art. All words used inthe claims are intended to be used in the normal, customary usage ofgrammar, the trade and the English language.

BRIEF DESCRIPTION OF THE DRAWINGS

The stated and unstated objects, features and advantages of the presentinventions (sometimes used in the singular, but not excluding theplural) will become apparent from the following descriptions anddrawings, wherein like reference numerals represent like elements in thevarious views, and in which:

FIG. 1 is a side plan view of a preferred embodiment of a burner tube ofthe present invention, shown with a preferred air shutter and analternative embodiment of a venturi member installed and shown with theclosed end prior to closure;

FIG. 2 is an exploded perspective view of the components of theembodiment of FIG. 1 and showing the closed end of the burner tubeclosed;

FIG. 3 is a side plan view of a preferred embodiment of the burner tubeof the present invention of FIG. 1;

FIG. 4 is a top plan view of the preferred burner tube of FIG. 3;

FIG. 5 is a perspective view of the preferred burner tube of FIG. 3 andshowing the closed end of the burner tube open;

FIG. 6 is a cross-sectional detail view of the preferred raised gasports of the present invention;

FIG. 7 is a top detail plan view of the preferred raised gas ports ofthe present invention;

FIG. 8 is a perspective view of an embodiment of a venturi member of thepresent invention;

FIG. 9 is a perspective view of a preferred air shutter of the presentinvention;

FIG. 10 is a perspective view of a preferred embodiment of a venturimember of the present invention;

FIG. 11 is a side view of the preferred embodiment of the venturi memberof FIG. 10; and,

FIG. 12 is a cross-sectional view of portions of a preferred embodimentof the venturi member of the present invention installed in a typicalpreferred burner tube of the present invention and showing the areas ofsmooth and turbulent flow of the gas/air mixture.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Set forth below is a description of what is currently believed to be thepreferred embodiments or best representative examples of the inventionsclaimed. Future and present alternatives and modifications to theembodiments and preferred embodiments are contemplated. Any alternativesor modifications which make insubstantial changes in function, purpose,structure or result are intended to be covered by the claims of thispatent.

The overall aspects of a burner assembly 10 of the present inventionsmay be seen by reference to FIGS. 1 and 2. Burner assembly 10 includes apreferred burner tube 20, an air shutter 50 and a venturi member 60. Apreferred embodiment of venturi member 60 is shown in FIGS. 10-12.Preferred burner tube 20 has a length between an open end 21 and aclosed end 22. Open end 21 is typically toward the front of the grilladjacent to a gas valve and gas distribution manifold (not shown) andthe closed end 22 is typically secured to the rear of a grill. In mostsituations, a grill will include a plurality of burner tubes 20 spacedparallel to each other. As will be understood by those of skill in theart, the present inventions are equally applicable to grills having thecontrols on the side and burner tube 20 extending from side to side ofthe grill.

In a preferred embodiment, burner tube 20 has a rectangularcross-sectional shape, with an upper surface 23, two side surfaces 24,25 and a bottom surface 26 forming a substantially hollow interior. Itwill be understood by those of skill in the art that the cross-sectionalshape of burner tube 20 does not have to be rectangular, as in thepreferred embodiment. For example, the cross-sectional shape may besquare, circular or oval. It will be further understood that the venturimembers 60 of the present inventions may also be used withnon-rectangular burner tubes 20. In the preferred embodiment, the burnertube 20 is tapered, i.e., there is a gradual decrease in cross-sectionalarea along the length from the open end 21 to the closed end 22. Thispermits a constant pressure of the fuel/air mixture throughout thelength of the burner tube 20. A window 28 is provided on each side 24,25 near the open end 21 of burner tube 20. The window 28, in conjunctionwith air shutter 50 (FIG. 9), is used to adjust the air/fuel mixture aswill be understood by those of skill in the art. In addition, a venturimember 60 is provided which accelerates the gas/air mixture introducedinto burner tube 20 which helps draw in combustion air, mix the gas andcombustion air and equalize pressure and velocity. A preferred venturimember 60 also provides smooth and consistent flow along the length ofthe tube 20 adjacent to the gas ports 30.

A plurality of gas ports 30 are also provided. In a preferredembodiment, gas ports 30 are equally spread along the top surface 23 ofthe burner tube 20. It will be understood by those of skill in the artthat the number and spacing of ports, as well as the size of thecross-sectional shape of burner tube 20, is calculated or determinedbased upon the BTU's desired from each burner tube 20. Importantly, thegas ports 30 are formed or extruded from the inside of tube 20 to theoutside of tube 20. In this manner, unlike conventional burner tubeswhich are punched from the outside to the inside of the tube, there areno burrs or obstructions on the inside of the burner tube 20 to obstructthe fuel/air flow or to make that flow turbulent. As a result, desirableblue flame characteristics, among other advantages, are achieved.

In the preferred embodiment and preferred method of its manufacture,burner tube 20 is constructed from a single sheet of appropriately sizedand shaped material, typically stainless steel. On what will become theinside of burner tube 20, gas ports 30 are formed or extruded on whatwill be the top surface 23. Once the ports 30 are formed from the insideto the outside, the sheet of material is then folded to form the upper23 and side surfaces 24, 25, as well as bottom surface 26. A tab 27 isprovided and welded together so that a substantially hollow, tapered andburr-free burner tube 20 is formed. See FIGS. 1, 2, 3 and 5. It will beunderstood by those of skill in the art that there are methods, otherthan the preferred method, of manufacturing tapered burner tube 20 andports 30 consistent with the goals and objects of the presentinventions.

The preferred raised gas ports 30 of the present inventions may betterbe seen by reference to FIGS. 6 and 7. Each port 30 has a height 32measured from the upper surface 23 with an opening 33 at the top of theheight 32. Each opening 33 has a diameter 34. In the preferredembodiment, the openings 33 are circular. It will be understood by thoseof skill in the art that openings 33 may be another shape and that thedimensions discussed herein for diameter may be readily converted toarea if, for example, square or rectangular openings are used. Becausethe opening 33 of port 30 is raised above upper surface 23 of burnertube 20, the flame is also lifted above upper surface 23 of burner tube20. This improves flame quality and reduces the temperature of tube 20during grilling, which increases the life of the tube 20 and preventscorrosion and clogging of the port openings 33. It will be understood bythose of skill in the art that ports 30 may alternatively be located onone or both side surfaces 24, 25. It will also be understood thatnon-rectangular shapes of burner tube 20 may also be used consistentwith the present inventions.

Tests have shown that the ratio of port height 32 to port opening 33diameter 34 is important to proper and efficient flame quality andburner tube 20 longevity. The ideal theoretical port height 32 to portopening 33 diameter 34 is 1:1. However, in practice, that ratio isunobtainable when cost effectively manufacturing a burner tube 20 of thepresent inventions. Since the ports 30 are typically formed from thematerial of upper surface 23, there is only so much material availableto form the ports 30, as will be understood by those of skill in theart. In addition, tests have also shown that in burner tubes 20 sizedfor use in typical gas grills, the port opening 33 diameter 34 shouldnot exceed 0.110″ to avoid flame pullback into burner tube 20. Thus, ithas been determined that the maximum, reasonably feasible port height 32is approximately 0.020″ to 0.062″. And, the preferred port opening 33diameter 34 is between approximately 0.075″ and 0.110″. In the preferredembodiment, the port height 32 to opening diameter 34 ratio isapproximately 0.645. This preferred ratio is achieved using a preferredport height 32 of 0.060″ and a preferred port opening diameter 34 of0.093″. This preferred configuration, along with the taper of burnertube 20, provides the best flame quality, reduces clogging and extendsthe life of the burner tube 20.

An alternative embodiment of a venturi member 60 may be seen byreference to FIG. 8. Venturi member 60 includes a front face 61 havingan opening 62 to accommodate the neck of a typical gas valve (notshown). A rearwardly projecting side tab 63 having a hole 64 is alsoprovided on each side of front face 61. A top flange 65 and a bottomflange 66 project rearward of face 61. Top flange 65 includes a v-shapedportion having an apex 67. Similarly, bottom flange 66 includes aninverted v-shaped portion having an apex 68. As can be seen in FIG. 8,the space between the top and bottom flanges 65 and 66 becomesconstricted, forming what is commonly known as a throat or throat area(76 in FIGS. 10 and 11), where the two opposing apexes 67 and 68converge. A stabilizer brace 69 is provided at the rear of the member tosupport the upper and lower flanges 65 and 66 and maintain their spacingwhen installed into the open end 21 of burner tube 20. A hole 70 may beprovided on upper flange 65 near the front in order to accommodate ascrew used to secure air shutter 50 to the burner tube 20 (see FIGS. 2and 9), as hereinafter described.

As shown in FIGS. 1 and 2, venturi member 60 is inserted into the openend 21 of burner tube 20. It may be affixed to the burner tube 20 usinga screw (not shown) through hole 64 of tab 63 into holes 71 in the sides24, 25 of burner tube 20. It will be understood that other means may beused to attach venturi member 60 to burner tube 20. When inserted intoburner tube 20, the neck of a typical gas valve (not shown) is insertedinto opening 62. As the fuel/air mixture passes between the spacebetween upper apex 67 and lower apex 68, it velocity is increased. Itwill be understood by those of skill in the art that venturi member 60is shaped and sized to fit within the open end 21 and coincides with thecross-sectional shape of burner tube 20.

A preferred embodiment of venturi member 60 may be seen by reference toFIGS. 10, 11 and 12. Like the above described alternative venturi member60, preferred venturi member 60 includes a front face 61 having anopening 62 to accommodate the neck of a typical gas valve (not shown). Atop flange 65 and a bottom flange 66 are also provided. A hole 70 may beprovided on top flange 65 which may be used to secure venturi member 60and/or air shutter 50 to burner tube 20. Although not shown in FIGS. 10and 11, side tabs 63 (see FIG. 8) may be provided on the preferredembodiment if desired as a means of attachment to the burner tube 20.

The top flange 65 and bottom flange 66 of preferred venturi member 60are generally parallel to each other in the portion of venturi member 60that receives the gas from the gas nozzle (not shown) and where it isattached to open end 21 of burner tube 20. Top flange 65 extendsrearwardly from face 61 to a top transition point 72. Similarly, bottomflange 66 extends rearwardly to a bottom transition point 73.

Extending rearwardly from top transition point 72 is a top constrictingflange 74. Top constricting flange 74 extends downwardly from toptransition point 72. Top constricting flange 74 may be straight orslightly curvilinear as shown in FIGS. 10 and 11. Similarly, extendingrearwardly from bottom transition point 73 is an upwardly sloping bottomconstricting flange 75. Top constricting flange 74 and bottomconstricting flange 75 converge at throat area 76. Throat area 76 ofpreferred venturi member 60 forms the narrowest space in venturi member60 and is roughly the equivalent of the space between v-shaped top apex67 and inverted v-shaped bottom apex 68 of the embodiment as shown inFIG. 8. Throat region 76 accelerates and helps mix the gas and airintroduced into burner tube 20. A stabilizer brace 69 may also beprovided.

Extending rearwardly of top constricting flange 74 and beginning atapproximately throat area 76 is an upper arcuate portion 77. Upperarcuate portion 77 is generally concave and terminates at a heightapproximately equivalent in height to top flange 65. Upper arcuateportion 77 serves to, among other things, occupy the space near the topof the burner tube 20 where undesirable turbulence could form near thegas ports 30. Extending rearwardly from bottom constricting flange 75and beginning at approximately throat area 76 is a lower arcuate portion78. Lower arcuate portion 78 includes a concave portion 79 and a convexportion 80. As shown in FIG. 11, lower arcuate portion 78 transitionssmoothly in an undulating fashion between concave portion 79 and convexportion 80. Lower arcuate portion 78 terminates at a point roughlyequivalent in height to bottom flange 66.

As shown in FIGS. 11 and 12, the concave portion 79 of lower arcuateportion 78 forms a first area of turbulence 81. A second area ofturbulence 82 is created after convex portion 80 of lower arcuateportion 78. The end of convex portion 80 roughly coincides with thebottom 26 of burner tube 20. The unique shape of upper arcuate portion77 occupies the space at the top of burner tube 20 where undesiredturbulence may most likely occur. Lower arcuate portion 78 creates whatis commonly known as a coanda effect at the bottom 26 of burner tube 20.Specifically, as the gas/air mixture is accelerated and leaves throatarea 76, turbulence is created in the first 81 and second 82 areas ofturbulence (see FIG. 12). The smooth, undulating lower arcuate portioncreates the desired coanda effect in the first and second areas ofturbulence 81/82. The areas of turbulence 81/82 are created at thebottom portion of burner tube 20 such that an area of smooth flow 83 iscreated in the upper portion of burner tube 20 adjacent to the gas ports30 (see FIG. 12). This creates smooth and uniform flow at gas ports 30,creating better, more stable and uniform flows resulting in better flameconsistency along the length of the burner tube 20. It also provides forbetter ignition (see FIG. 12).

It will be understood by those of skill in the art that the length ofsmoothly curved arcs in lower arcuate portion 78, as well as theircurvature, may be adjusted depending upon, among other things, thevolume of the burner tube 20, the length of burner tube 20 and thearrangement of the gas ports 30. In addition, if desired, additionalconcave 79 and convex 80 portions may be provided by extending thelength of lower arcuate portion 78 along the length of burner tube 20.It has been determined, however, that two such portions are effective increating the desired coanda effect in burner tube 20 of the size,configuration and volume typically used in grilling applications. Inaddition, it will be understood by those of skill in the art that theabove described arcuate portions of upper 77 and lower 78 arcuateportions may be formed from a single piece of material or may beseparate pieces of material attached together, such as by welding.

A preferred air shutter 50 of the present inventions may be seen byreference to FIG. 9. As will be understood by those of skill in the art,air shutter 50 cooperates with the window 28 at the open end 21 ofburner tube 20 to permit adjustment of the combustion air to fuelmixture. Preferred shutter 50 includes a top 51 having a slot 52 whichis used to secure shutter 50 through hole 72 to burner tube 20 once inthe proper position for the desired mixture. Shutter 50 includes twosides 53, each having a recess 54 and two bottom sections 55. It will beunderstood by those of skill in the art that a space between bottommembers 55 is provided to accommodate tab 27 on the bottom of burnertube 20 that is part of a preferred manufacturing process. The recesses54 of sides 53 accommodate the attachment flanges 63 of venturi member60 when it is attached to burner tube 20.

When in use, the neck of a gas valve is inserted into opening 62 ofventuri member 60 with the open end of burner tube 20 typically at thefront of the grill. The closed end 22 of burner tube 20 is movablysecured to a rear of the grill and the open end slidingly connected tothe valve neck by the air shutter 50. In this manner, tube 20 may expandand contract as necessary during use. The gas is injected into venturimember 60 and mixed with the desired amount of combustion air using airshutter 50. The velocity of the fuel/air mixture is accelerated by theventuri member 60 (and in particular throat area 76 of the preferredembodiment of venturi member 60 and between v-shaped apex 67 andinverted v-shaped apex 68 of the venturi 60 embodiment of FIG. 8) andflows down the length of burner tube 20. Because of the taper of burnertube 20, the pressure throughout the length of the tube 20 is relativelyconstant. And, because of the unique configuration of preferred venturimember 60 (see FIGS. 10 and 11), smooth and stable flow 83 along the topof burner tube 20 adjacent to ports 30 is created (see FIG. 12).

When lit, the flame sits on top of the raised gas ports 30 at theopening 33. Since the flame is lifted off of the upper surface 23 ofburner tube 20, the burner tube 20 remains cooler. This results in lessport 30 clogging and less corrosion of the burner tube 20. In thismanner, a longer life of burner tube 20 and high flame quality may beachieved. In addition, when the preferred port height 32 to port opening33 diameter 34 is used, flame quality is further increased.

The above description is not intended to limit the meaning of the wordsused in or the scope of the following claims that define the invention.Rather, it is contemplated that future modifications in structure,function or result will exist that are not substantial changes and thatall such insubstantial changes in what is claimed are intended to becovered by the claims. Thus, while preferred embodiments of the presentinventions have been illustrated and described, it will be understoodthat changes and modifications can be made without departing from theclaimed invention. In addition, although the term “claimed invention” or“present invention” is sometimes used herein in the singular, it will beunderstood that there are a plurality of inventions as described andclaimed.

Various features of the present inventions are set forth in thefollowing claims.

What is claimed is:
 1. A venturi member for use in a burner tube for agas grill, the burner tube having a length, a top with gas ports and abottom, the venturi member comprising: a front face having a top and abottom, the front face including an opening to accommodate a neck of agas valve; a top flange extending rearwardly from the top of the frontface and a substantially parallel bottom flange extending rearwardlyfrom the bottom of the front face; a downwardly sloping top constrictingflange extending rearwardly from the top flange and an upwardly slopingbottom constricting flange extending rearwardly from the bottom flange,the top constricting flange and bottom constricting flange converging toform a throat area; an upper arcuate portion extending rearwardly fromthe top constricting flange; and, a lower arcuate portion extendingrearwardly from the bottom constricting flange.
 2. The venturi member ofclaim 1 wherein the upper arcuate portion has a concave shape generallyadjacent to the top of the burner tube.
 3. The venturi member of claim 1wherein the lower arcuate portion has a concave portion and a convexportion generally adjacent to the bottom of the burner tube.
 4. Theventuri member of claim 2 wherein the lower arcuate portion has aconcave portion and a convex portion generally adjacent to the bottom ofthe burner tube.
 5. The venturi member of claim 2 wherein the upperarcuate portion occupies the space where turbulence may form along thetop of the burner tube and adjacent to the gas ports.
 6. The venturimember of claim 3 wherein a first turbulence area is created in theconcave portion of the lower arcuate portion and a second turbulencearea is created adjacent to the end of the convex portion of the lowerarcuate portion.
 7. The venturi member of claim 4 wherein the upperarcuate portion occupies the space where turbulence may form at the topof the burner tube adjacent to the gas ports and a first turbulence areais created in the concave portion of the lower arcuate portion and asecond turbulence area is created adjacent to the end of the convexportion of the lower arcuate portion.
 8. The venturi member of claim 1wherein the top constricting flange is arcuate.
 9. A burner for use in agas grill, comprising: a tapered burner tube having an open end, aclosed end and a substantially hollow and smooth interior which is freeof burrs or other obstructions and an upper surface, the upper surfaceincluding a plurality of gas ports having a height projecting above theupper surface and an opening at the top of the height, the openinghaving a diameter; a venturi member at the open end of the burner tube,the venturi member including: a front face having a top and a bottom,the front face including an opening to accommodate a neck of a gasvalve; a top flange extending rearwardly from the top of the front faceand a substantially parallel bottom flange extending rearwardly from thebottom of the front face; a downwardly sloping top constricting flangeextending rearwardly from the top flange and an upwardly sloping bottomconstricting flange extending rearwardly from the bottom flange, the topconstricting flange and bottom constricting flange converging to form athroat area; an upper arcuate portion extending rearwardly from the topconstricting flange wherein the upper arcuate portion has a concaveshape generally adjacent to the top of the burner tube; and, a lowerarcuate portion extending rearwardly from the bottom constricting flangewherein the lower arcuate portion has a concave portion and a convexportion generally adjacent to the bottom of the burner tube.
 10. Theburner of claim 9 wherein the upper arcuate portion occupies the spacewhere turbulence may form at the top of the burner tube adjacent to thegas ports and a first turbulence area is created in the concave portionof the lower arcuate portion and a second turbulence area is createdadjacent to the end of the convex portion of the lower arcuate portion.11. The burner of claim 10 wherein the gas port height is betweenapproximately 0.020 and 0.062 inches and the gas port opening diameteris between approximately 0.075 and 0.110 inches.
 12. The burner assemblyof claim 11 wherein the gas port height is approximately 0.060 inchesand the port diameter is approximately 0.093 to 0.99 inches.
 13. Theburner assembly of claim 10 wherein a ratio of gas port height to gasport opening diameter is between approximately 0.640 and 0.650.
 14. Theburner assembly of claim 13 wherein the gas port height to gas portopening diameter ratio is greater than 0.5.
 15. The burner assembly ofclaim 10 wherein the height of the gas ports is between 0.020 and 0.062inches and the area of the gas port opening is between 0.006 and 0.008square inches.
 16. The burner assembly of claim 10 wherein the height ofthe gas port is approximately 0.060 inches and the area of the gas portopening is approximately 0.007 square inches.
 17. The burner assembly ofclaim 9 wherein an air shutter is provided that cooperates with the openend of the burner tube to permit adjustment of the fuel and air mixturegoing into the burner tube.
 18. The burner assembly of claim 10 whereinthe port opening is generally circular, having a diameter.
 19. Theburner assembly of claim 18 wherein the height of the gas ports isbetween 0.020 and 0.062 inches and the diameter of the opening isbetween 0.075 and 0.110 inches.
 20. The burner assembly of claim 19wherein the height of the gas ports is approximately 0.060 inches andthe diameter of the opening is approximately 0.098 inches.